Bell alarm damping device



March 30, 1965 H. ALBINGER, JR

BELL ALARM DAMPING DEVICE Filed May 15, 1963 ywyw f/As 6550/1763 United States Patent 3,175,352 BELL ALARM DAMPllNG DEVKE Harry Aibinger, in, Ashland, Mass., assignor to General Electric Company, a corporation of New York Filed May 33, 1963, Ser. No. 279,393 8 Qlaims. (Cl. 58--l6) This invention relates to a bell alarm for an alarm clock or similar device and more particularly to an arrangement for controlling undesirable vibration of the bell striking assembly.

In spite of the wide spread usage of high speed vibrators to obtain a buzzing sound as an alarm in clocks and similar devices, there is still a demand for the slower moving bell-type alarm in view of the various sound effects and tonal qualities which may be obtained with such beii alarms. For example, some people may prefer the sound produced by a slowly repeating bell-type alarm as opposed to the sounds obtained from rapidly vibrating devices. One difliculty with such slowly repeating alarms is that alarm hammer springs strong enough to move the hammer with adequate force to produce a sound of the desired loudness tend to vibrate and strike the bell more than once each time the spring is released. A satisfactory solution to such a problem in addition to preventing the undesired vibration must be simple and low in cost to be practical.

Accordingly, it is a primary object of the present invention to provide an improved means for eliminating undesirable vibrations in a bell alarm vibrator arm.

it is a further object of the invention to provide a unique low-cost device for snubbing undesirable vibrations in a low frequency alarm hell with such device being easy to manufacture and not requiring adjustment after manufacture.

Briefly stated, the invention relates to a clock of the type including a bell and a hammer arm with a bell hammer attached thereto. The arm is so situated with respect to the bell that the hammer is normally positioned adjacent the bell. To sound the alarm, there is provided a clock driven force for engaging the hammer arm in a manner to move the hammer away from the bell and then release the arm to permit the hammer to strike the bell. The clock may be further provided with the conventional arrangement for preventing movement of the hammer arm and the hammer except during a predetermined alarm period and with a manual shut-oil for preventing movement of the hammer arm. When the hammer is permitted to strike the bell, there is a tendency for the hammer arm to vibrate to cause the hammer to strike the bell more than once. To prevent such occurrence, there is provided an element producing a force on the hammer arm in a direction perpendicular to the vibrational plane of the arm. This simple but unique arrangement effectively snubs movement of the hammer arm to prevent the hammer from striking the bell more than once each time the arm is actuated by the clock driven force.

The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, both as to organization and method of operation together with further objects and advantages thereof may best be understood by reference to the followihg description taken in connection with the accompanying drawings, in which:

FlG. 1 is a rear perspective view of the internal components of an alarm clock embodying the invention;

FIG. 2 is a top plan view of the alarm mechanism of FIG. 1;

FIG. 3 is a perspective view of the snubbing or damp ing element of the invention; and

FIG. 4 is a side elevational view of the alarm striking mechanism shown in FIG. 1.

Referring now to the drawings, and first particularly to PEG. 1, there is shown a rear view of an alarm clock including a front support plate 2, a middle support plate 4 connected by a plurality of pillars, one of which is shown at (5, to the stator section of a typical self-starting synchronous electric motor 8. The motor 8 drives a suitable timing unit ill which in turn is connected to drive a suitable gear train, portions of which are shown at 12 and 14. Although not shown, it is to be understood that the clock will of course be also provided with the other usual clock components such as the hands and face. The hands may be set by a typical manual control 16.

Turning now to the alarm mechanism of the clock, there is provided an elongated, flat hammer spring or arm 18 made of phosphor bronze or other flexible material and having one end fixed by suitable fastening members 20 to the middle support plate 4. On the movable end of the spring '18 there is mounted a hammer 22 which cooperates with a bell 24 to provide the desired alarm signal. As can be seen from FIG. 1, the bell is attached by a suitable centrally located fastening device 26 to the front plate 2.

The spring 18 is spaced slightly above the upper edge of middle support plate 4 with its major flat surface in roughly perpendicular relation to the plate. In its unstressed position, the spring 18 is normally positioned so that the hammer 22 is slightly spaced from hell 24. Therefore, it will be readily understood that the hammer 22 may be made to strike the bell 24 by moving the free end of the spring arm 18 upwardly and then releasing the spring so that the flexibility of the spring causes the hammer to be sharply struck against the surface of the bell.

To provide such movement the clock is equipped with a rotary gear 28, seen in FIGS. 2 and 4, which is continuously rotated by the clock mechanism. The gear 28 is integrally formed or otherwise suitably connected to a cam gear 30 having a plurality of teeth or projections forming cam surfaces. The spring 18 is provided with a projection 32 having a vertically disposed depending portion 320 and a horizontally extending portion 3212, as seen in FIGS. 2 and 4. The horizontally extending portion 32b extends into the path of the cam gear teeth so that when a tooth strikes the projection the movable part of spring 18 is bent in a clockwise direction about its fixed end as viewed in FIG. 1. This action of course raises the hammer 22 further away from bell 24. As the cam gear 30 continues to rotate the projection 32b drops into a space between the cam gear teeth thus permitting the spring 18 to move in response to its own flexibility causing hammer 22 to move in a counterclockwise direction and strike the bell. Naturally, the gear 28 and cam gear 30 may be rotated at the speed desired to obtain the desired sound from the bell and hammer. It has been found that one pleasing sound effect may be obtained by allowing the hammer to strike at a frequency rate of once per second or less. Also, by providing irregular spacing between the teeth of cam gear 30 irregular or intermittent ringing may be obtained in the desired sequence.

One problem encountered with such slow moving bell sounding mechanisms is that when the spring iii is bent or flexed by the cam 30 an amount sufiicient to obtain the desired loudness of the sound when the hammer strikes the bell, there is a tendency for the spring to vibrate rapidly due to its own flexibility and inertia several times before its projection 32 is engaged long enough by the next tooth of the cam gear 3% to move the hammer away from the bell. In accordance with the invention, this problem is solved by providing a simple but unique snubbing or damping element 36 which satisfactorily eliminates such spurious vibration rapidly enough to prevent the hammer from striking the bell more than once each time the hammer spring is raised by a cam tooth or surface.

As can be seen from the drawings, the snubbing or damping element 36 is a flat elongated member having an enlarged portion 36a with aperatures for facilitating mounting on the middle support plate 4. It should be noted that the number of parts required for the mechanism are minimized by mounting the snubbing element 36 and the spring 18 with the same fastening devices 20. As seen from the drawings, the end 361; of the element engages a downwardly extending portion 38 of the spring 18. The flat surface of element 36 is arranged in substantially pependicular relation to the major flat surface of spring 18. Thus, in efiiect the element 36 contacts an edge surface of spring 13. Since the spring portion 38 extends rearwardly from the plane of end 36a of element 36 when the element is attached to the supporting plate, the opposite end 3617 is forced a small distance to the rear. This produces a slight stress on the spring-like element 36 which is made of phosphor bronze or other suitable flexible material. This, in turn, produces an edgewise force on spring 18 which is substantially perpendicular to the direction of the spring vibration.

It has been found that this simple arrangement provides an extremely effective way to eliminate the undesirable vibration. Since the spring 18 is relatively long and thin so that it flexes easily, it has been found that only a slight edgewise force is required to eliminate the vibration. Thus, element 36 need not be stressed very greatly. On the other hand, it has also been found that the range of force required to produce the necessary damping is not very narrow or precise so that effective snubbing or damping action may be obtained utilizing mass produced components with relatively large manufacturing tolerances. Therefore, a. cost saving is obtained by not requiring an adjusting operation.

To obtain typical alarm clock operation, the clock is further provided with a suitable arrangement which normally holds the spring arm 18 out of engagement with the cam 31 except when automatically released by the clock mechanism during a predetermined alarm period. Since such arrangements are well known and do not form an important part of the present invention an example of such will not be shown or described. However, a suitable location in which such a control element could be placed to move the spring 18 is beneath the rearwardly extending tab 40 portion which is integrally connected with the depending portion 38 on spring 18. When the tab is released the spring will move downwardly unless otherwise restrained.

The clock should also be provided with a suitable manual control for shutting oft" the alarm at will and for releasing the alarm when automatic alarm operation is desired. For this purpose, there is provided a shut-oil lever 42, FIG. 1, slidably mounted in slots formed in middle plate 4 and a plate extension 44 mounted on the stator of motor 8. The lever 42 is provided with a cam portion 46 which is sloped to cooperate with a similarly sloped portion 48 integrally formed with tab 4% of spring 18. It is no doubt readily apparent that when the lever 4-2 is pushed inwardly toward the front of the clock, surface 46 engages portion 48 causing the tab as and spring 18 to move upwardly so that the projection 32 is held out of driving engagement with cam 30. Conversely, when the lever 42 is pulled rearwardly spring arm 18 is released. It should be noted that a minimum number of parts are required by forming projection 32 and portions 38, 40 and 48 integrally with the spring 8.

While the invention has been described with reference to a particular embodiment, it is to be understood that the embodiment is illustrative in character and that changes are contemplated within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

1. in a clock, a bell, a movable hammer arm, a bell hammer attached to the hammer arm, said arm being so positioned that the hammer is positioned in striking relation to said bell, means for moving said arm to move said hammer away from said bell and for releasing said arm to permit said hammer to strike said bell, and means for preventing said hammer from striking said bell more than once each time said arm is moved by said arm moving means comprising a flexible element producing a friction force on said arm in a direction substantially perpendicular to the striking movement of said arm.

2. In a clock, a bell, a flexible hammer spring having a fixed portion and a movable portion, a bell hammer attached to the movable portion of said spring, said spring being so positioned that the hammer is positioned in striking relation to said bell, means for moving said spring to move said hammer away from said bell and for releasing said spring to permit said hammer to strike said bell, and means for preventing said hammer from striking said bell more than once each time said spring is moved by said spring moving means comprising a flexible element producing a force on said spring in a direction substantially perpendicular to the striking movement of said spring.

3. In an alarm clock, an alarm bell, a flat flexible hammer spring having one fixed end and one movable end, a bell hammer attached to the movable end of said spring, said spring being so positioned that the hammer is in striking relation with said bell, means for flexing said spring to move said hammer away from said bell and for releasing said spring to permit said hammer to strike said bell, clock means for preventing movement of said spring and hammer except during a predetermined alarm period, manual means for preventing movement of said spring by said cam, and means for preventing said hammer from engaging said bell more than once each time said spring is moved by said spring flexing means comprising a flexible element producing an edgewise force on said spring.

4. In a clock, a bell, a flat flexible hammer spring having one fixed end and one movable end, a bell hammer attached to the movable end, said spring and hammer being arranged so that the hammer may engage said hell by the movement of said spring, means for engaging said spring to move said hammer away from said bell and for releasing said spring to permit said hammer to strike said bell, and a fiat flexible element having its flat surface arranged in perpendicular relation to the flat surface of said spring, said element having one end fixed with respect to said spring fixed end and having its other end engaging the movable portion of said spring to provide a damping action which present said hamrner from striking said bell more than once each time said spring is moved and released by said cam gear.

5. In an alarm clock, an alarm bell, a fiat flexible hammer spring having a fixed portion and a movable portion, a bell hammer attached to the movable portion and positioned to be struck against said bell, a continuously rotating cam gear for moving said spring in a manner to move said hammer away from said bell and for releasing said spring to permit said hammer to strike said bell, clock means for preventing said cam from moving said spring and hammer except during a predetermined alarm period, manual means movable at will for preventing said cam from moving said spring, and a flat flexible element having its flat surface contacting said spring in perpendicular relation to the flat surface of said spring, said element having one end fixed with respect to said spring fixed end and having its other end urging against the movable portion of said spring to provide a damping action which prevents said hammer from strik ing said bell more than once each time said spring is moved and released by said cam gear.

6. In an alarm clock, a flexible hammer spring having a fixed portion and a movable portion, a bell hammer attached to the movable portion of said spring, a bell positioned in the path of said hammer, a clock driven cam gear, said spring having a projection extending into the path of said cam gear teeth so that the cam surfaces move and release said spring at a predetermined frequency causing said hammer to be moved away from said bell and released to strike said bell at the predetermined frequency, a portion depending from said spring movable portion and a flexible element engaging said depending portion of said spring to provide a force on said spring in a direction substantially perpendicular to the striking movement of said spring for quickly damping vibration of said spring whenever said spring is moved and released by said cam gear.

7. In an alarm clock, a flexible hammer spring having a fixed portion and a movable portion, a hell hammer attached to the movable portion of said spring, a bell positioned in the path of said hammer, rotary means for flexing and releasing said spring at a predetermined frequency causing said hammer to strike said bell at the predetermined frequency, a tab extending from said spring movable portion, clock means for engaging said tab to prevent said rotary means from actuating said spring except during a predetermined alarm period, manual means movable at Will to engage said tab for preventing said rotary means from actuating said spring and a flexible t5 element engaging said spring and exerting a damping force on said spring in a direction substantially perpendicular to the striking movement of said spring for quickly damping vibration of said spring so that said hammer only engages said bell once each time said spring is flexed and released by said rotary means.

8. In an alarm clock, an alarm bell, a flexible hammer spring having a fixed end and a movable end, a bell hammer attached to the movable end of said spring, said spring being so positioned that the hammer is positioned in striking relation to said bell, means for moving said spring to move said hammer away from said bell and for releasing said spring to permit said hammer to strike said bell, and means for preventing said hammer from striking said bell more than once each time said spring is moved by said spring moving means comprising a flexible element having one end fixed with respect to the fixed end of said hammer spring and having its other end engaging said spring intermediate the spring ends to produce force on the spring in a direction substantially perpendicular to the striking movement of said spring.

References Cited by the Examiner UNITED STATES PATENTS 30,800 12/60 Chandler 116-l64 370,038 9/ 87 Beyerle 58-9 2,851,850 9/58 Fowler 589 LEO SMILOW, Primary Examiner.

JOSEPH P. STRIZAK, Examiner. 

1. IN A CLOCK BELL, A MOVABLE HAMMER ARM, A BELL HAMMER ATTACHED TO THE HAMMER ARM, SAID ARM BEING SO POSITIONED THAT THE HAMMER IS POSITIONED IN STRIKING RELATION TO SAID BELL, MEANS FOR MOVING SAID ARM TO MOVE SAID HAMMER AWAY FROM SAID BELL AND FOR RELEASING SAID ARM TO PERMIT SAID HAMMER TO STRIKE SAID BELL, AND MEANS FOR PREVENTING SAID HAMMER FROM STRIKING SAID BELL MORE THANN ONCE EACH TIME SAID ARM IS MOVED BY SAID ARM MOVING MEANS COMPRISING A FLEXIBLE ELEMENT PRODUCING 